Minimally invasive surgical training using robotics and telecollaboration

ABSTRACT

A medical system that allows a mentor to teach a pupil how to use a robotically controlled medical instrument. The system may include a first handle that can be controlled by a mentor to move the medical instrument. The system may further have a second handle that can be moved by a pupil to control the same instrument. Deviations between movement of the handles by the mentor and the pupil can be provided as force feedback to the pupil and mentor handles. The force feedback pushes the pupil&#39;s hand to correspond with the mentor&#39;s handle movement. The force feedback will also push the mentor&#39;s hand to provide information to the mentor on pupil&#39;s movements. The mentor is thus able to guide the pupil&#39;s hands through force feedback of the pupil handles to teach the pupil how to use the system.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.10/948,853, now U.S. Pat. No. 7,413,565, which is a divisional of U.S.application Ser. No. 10/246,236, now U.S. Pat. No. 6,951,535, the fulldisclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a medical robotic system.

Historically, surgery has been performed by making large incisions in apatient to provide access to the surgical site. There has been developedinstruments that allow a surgeon to perform a procedure through smallincisions in the patient. The instruments include an endoscope which hasa camera that allows the surgeon to view the internal organs of thepatient through a small incision. Such procedures are less traumatic tothe patient and have shorter recovery times than conventional surgicalprocedures.

Such instruments have even been used to perform minimally invasive heartsurgery. Blockage of a coronary artery may deprive the heart of bloodand oxygen required to sustain life. The blockage may be removed withmedication or by an angioplasty. For severe blockage “a coronary arterybypass graft (CABG) is performed to bypass the blocked area of theartery. CABG procedures are typically performed by splitting the sternumand pulling open the chest cavity to provide access to the heart. Anincision is made in the artery adjacent to the blocked area. Theinternal mammary artery is then severed and attached to the artery atthe point of incision. The internal mammary artery bypasses the blockedarea of the artery to again provide a full flow of blood to the heart.Splitting the sternum and opening the chest cavity can create atremendous trauma to the patient. Additionally, the cracked sternumprolongs the recovery period of the patient.

Computer Motion of Goleta, Calif. provides a system under the trademarkZEUS that allows a surgeon to perform minimally invasive surgery,including CABG procedures. The procedure is performed with instrumentsthat are inserted through small incisions in the patient's chest. Theinstruments are controlled by robotic arms. Movement of the robotic armsand actuation of instrument end effectors are controlled by the surgeonthrough a pair of handles and a foot pedal that are coupled to anelectronic controller. Alternatively, the surgeon can control themovement of an endoscope used to view the internal organs of the patientthrough voice commands.

The handles and a screen are typically integrated into a console that isoperated by the surgeon to control the various robotic arms and medicalinstruments of a ZEUS system. Utilizing a robotic system to performsurgery requires a certain amount of training. It would be desirable toprovide a system that would allow a second surgeon to assist anothersurgeon in controlling a robotic medical system. The second surgeoncould both teach and assist a surgeon learning to perform a medicalprocedure with a ZEUS system. This would greatly reduce the timerequired to learn the operation of a robotically assisted medicalsystem.

U.S. Pat. No. 5,217,003 issued to Wilk discloses a surgical system whichallows a surgeon to remotely operate robotically controlled medicalinstruments through a telecommunication link. The Wilk system onlyallows for one surgeon to operate the robotic arms at a given time. Wilkdoes not disclose or contemplate a system which allows two differentsurgeons to operate the same set of robotic arms.

U.S. Pat. No. 5,609,560 issued to Ichikawa et al. and assigned toOlympus Optical Co. Ltd. discloses a system that allows an operator tocontrol a plurality of different medical devices through a singleinterface. The Olympus patent does not disclose a system which allowsmultiple surgeons to simultaneously perform a surgical procedure.

BRIEF SUMMARY OF THE INVENTION

A medical system that includes a first input device that can move afirst input distance to move a first medical device and a second inputdevice that can move a second input distance to move said first medicaldevice. The system may further have a feedback device that can providean indication of a difference between the first and second inputdistances.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a medical robotic system;

FIG. 2 is a perspective view of a control unit;

FIG. 3 is a perspective view of a handle assembly of the control unit;

FIG. 4 is a perspective view of a handle/wrist subassembly;

FIG. 5 is a sectional perspective view of the handle/wrist subassembly;

FIG. 6 is an exploded side view of an instrument of the robotic system;

FIG. 7 is an illustration of a network system;

FIG. 8 is an illustration of a “surgeon” side of the network system;

FIG. 9 is an illustration of a “patient” side of the network system;

FIG. 10 is a schematic showing various fields of a packet transmittedacross a communication network;

FIG. 11 is an illustration showing an alternate embodiment of thenetwork system;

FIG. 12 is a schematic of a control system;

FIG. 13 is an illustration depicting collaboration between a mentor andpupil controlling a single degree of freedom instrument.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings more particularly by reference numbers, FIG. 1shows a system 10 that can perform minimally invasive surgery. In oneembodiment, the system 10 is used to perform a minimally invasivecoronary artery bypass graft (MI-CABG) and other anastomosticprocedures. Although a MI-CABG procedure is shown and described, it isto be understood that the system may be used for other surgicalprocedures. For example, the system can be used to suture any pair ofvessels. The system 10 can be used to perform a procedure on a patient12 that is typically lying on an operating table 14. Mounted to theoperating table 14 is a first articulate arm 16, a second articulate arm18, a third articulate arm 20, a fourth articulate arm 22 and a fiftharticulate arm 24 which may also be referred to as medical devices. Thearticulate arms 16, 18, 20, 22 and 24 are preferably mounted to thetable 14 so that the arms are at a same reference plane as the patient.Although five articulate arms are shown and described, it is to beunderstood that the system may have any number of arms.

The first 16, second 18, third 20 and fourth 22 articulate arms may eachhave a surgical instrument 26, 28, 30 and 32, respectively, coupled torobotic arms 34, 36, 38 and 40, respectively. The fifth articulate arm24 includes a robotic arm 42 that holds and moves an endoscope 44. Theinstruments 26, 28, 30 and 32, and endoscope 44 are inserted throughincisions cut into the skin of the patient 12. The endoscope 44 has acamera 46 that is coupled to video consoles 48 which display images ofthe internal organs of the patient.

The system 10 may include a mentor control unit (MCU) 50 and a pupilcontrol unit (PCU) 52. Each control unit 50 and 52 has a controller 54and a pair of handle assemblies 56 that allow a mentor surgeon at theMCU 50 to teach and assist a pupil surgeon at the PCU 52. The PCU 52 istypically in the operating room. The MCU 50 may be at a remote location.Each controller. 54 contains electrical circuits, such as aprocessor(s), memory, I/O interface, drivers, etc. that control themovement and actuation of robotic arms 34, 36, 38, 40 and 42 andinstruments 26, 28, 30 and 32. The surgeon can view a different portionof the patient by providing a voice command(s) that moves the arm 42holding the endoscope 44. The robotic arm(s) maybe devices that are soldby the assignee of the present invention, Computer Motion, Inc. ofGoleta, Calif., under the trademark AESOP. The system is also describedin U.S. Pat. No. 5,657,429 issued to Wang et al. and assigned toComputer Motion, which is hereby incorporated by reference.

Any two instruments 26, 28, 30 or 32 can be controlled by the handleassemblies 56 of each control unit 50 and 52. For example, instruments26 and 28 can be controlled by the handle assemblies 56 of the MCU 50and instruments 30 and 32 can be controlled by the handle assemblies ofthe PCU 52. Alternatively, a single instrument may be controlled byhandle assemblies 56 of both the MCU 50 and PCU 52.

The handle assemblies 56 and articulate arms 16, 18, 20 and 22 have amaster-slave relationship so that movement of the handles 56 produces acorresponding movement of the surgical instruments 26, 28, 30 and/or 32.The controller 54 receives input signals from the handle assemblies 56of each control unit 50 and 52, computes a corresponding movement of thesurgical instruments 26, 28, 30 and 32, and provides output signals tomove the robotic arms 34, 36, 38 and 40 and instruments 26, 28, 30 and32. The entire system may be similar to a product marketed by ComputerMotion under the trademark ZEUS. The operation of the system is alsodescribed in U.S. Pat. No. 5,762,458 issued to Wang et al. and assignedto Computer Motion, which is hereby incorporated by reference.

FIG. 2 shows a control unit 50 or 52. The handle assemblies 56 arelocated adjacent to a surgeon's chair 58. The handle assemblies 56 arecoupled to the controller 54. The controller 54 is coupled to therobotic arms 34, 36, 38, 40 and 42 and medical instruments 26, 28, 30and 32. The controller 54 may include one or more microprocessors,memory devices, drivers, etc. that convert input information from thehandle assemblies 56 into output control signals which move the roboticarms 34, 36, 38 and 40 and/or actuate the medical instruments 26, 28, 30and 32.

The surgeon's chair 58 and handle assemblies 56 may be in front of thevideo console 48. The video console 48 may be linked to the endoscope 44shown in FIG. 1 to provide video images of the patient. The control unit50 or 52 may also include a computer screen 60 coupled to the controller54. The screen 60 may display graphical user interfaces (GUIs) thatallow the surgeon to control various functions and parameters of thesystem 10. The control unit 50 or 52 may further have a microphone (notshown) to accept voice commands. One or more voice commands may be usedto move the endoscope. Other voice commands can be used to varyparameters of the system. The voice control and parameter changingsystem may be the same or similar to a product sold by Computer Motionunder the trademark HERMES.

Each handle assembly 56 may include a handle/wrist assembly 62. Thehandle/wrist assembly 62 has a handle 64 that is coupled to a wrist 66.The wrist 66 is connected to a forearm linkage 68 that slides along aslide bar 70. The slide bar 70 is pivotally connected to an elbow joint72. The elbow joint 72 is pivotally connected to a shoulder joint 74that is attached to the controller 54.

FIG. 3 shows a handle assembly 56 superimposed with a medical instrument26, 28, 30 or 32. The instrument 26, 28, 30 or 32 may include an endeffector 75 attached to an instrument shaft 77. The shaft 77 extendsthrough a cannula 78 inserted through an incision of a patient 12. Theincision defines a pivot point P for the medical instrument 26, 28, 30or 32.

The shoulder joint 74 includes a sensor (not shown) that providesfeedback on the movement of the handle 64 about a shoulder axis 76. Thesensor may be a mechanical encoder, optical encoder, etc. or otherdevice which provides an output signal that corresponds to a position ofthe handle 64 about the shoulder axis 76. The output of the shouldersensor is provided to the controller 54. The controller 54 performs aseries of computations to determine a corresponding movement of themedical instrument 26, 28, 30 or 32. The computations may include one ormore transformation and kinematic equations. The controller 54 providesoutput signals to the corresponding robotic arm to move the instrument26, 28, 30 or 32 as indicated by the arrow 79. The transformation andkinematic equations may be similar to the equations used in the AESOPand ZEUS products with the signs (+/−) reversed to account for theshoulder axis 76 being behind the surgeon.

The shoulder joint 74 may have a force actuator (not shown) that canprovide a resistive force to movement of the handle 64 about the axis76. The force actuator maybe an active device or a passive device suchas a friction clutch.

The elbow joint 72 includes a sensor (not shown) that providespositional feedback on the position of the assembly about an elbow axis80. The controller 54 utilizes the positional feedback to drive therobotic arm and move the instrument in the direction indicated by thearrow 82.

The elbow joint 72 may also have a force actuator (not shown) that canprovide resistance to movement of the handle about the axis 80. Whentransforming movement of the handle 64 to movement of the instrument 26,28, 30 or 32 the controller 54 may equate the elbow axis 80 to theinstrument pivot point P. Equating the elbow axis 80 with the pivotpoint P provides a kinematic relationship such that the surgeon “feels”like they are actually moving the instrument. Additionally, the lengthof the forearm linkage and location of the handle are such that thesurgeon is provided with the sensation that they are holding and movingthe distal end of the instrument. These relationships also improve theergonomics of the handle assembly and the ease of use of the roboticsystem as a whole.

The forearm linkage 68 and slide bar 70 create a translator 84 thatallows linear movement of the linkage 68 along a translator axis 86. Thetranslator 84 has a sensor (not shown) that provides feedbackinformation that is used to drive the robotic arm and move theinstrument 26, 28, 30 or 32 in the direction indicated by the arrows 88.The translator 84 may also have a force actuator (not shown) that canprovide resistance to movement along axis 86.

FIGS. 4 and 5 show the wrist/handle assembly 62. The wrist 66 includes ajoint shaft 90 that is coupled to the forearm linkage (not shown) by aroll bearing 92. The roll bearing 92 allows the handle 64 to rotateabout a roll axis 94. The wrist 66 may further include a sensor 96 thatprovides positional feedback to the controller 54. Movement of thehandle 64 about the roll axis 94 may cause a corresponding rotation ofthe instrument end effector 75 in the direction indicated by the arrows98 in FIG. 3. The wrist 66 may have a force actuator (not shown) thatprovides resistance to movement of the handle 64 about the roll axis 94.

The handle 64 includes a grasper 100 that is coupled to a handle housing102. The housing 102 and grasper 100 are preferably shaped as anellipsoid to allow the user to more easily grasp the handle 64 withtheir hand. The housing 102 may have a thumb groove 104 that receivesthe user's thumb. The grasper 100 may have a pair of grooves 106 and 108to receive the index and middle fingers of the user, respectively.

The handle 64 may spin about wrist axis 110. The handle 64 may include asensor 112 that provides positional feedback information to thecontroller 54 which is used to rotate the end effector 75 of the medicalinstrument 26, 28, 30 or 32 as indicated by the arrows 114 in FIG. 3.The handle 64 may also have a force actuator (not shown) that mayprovide resistance to rotation about axis.

The grasper 100 can be depressed by the user. The grasper 100 is coupledto a sensor 116 which provides feedback information to the controller54. The feedback information is used by the controller 54 to actuate theend effector 75 shown in FIG. 3. By way of example, depressing thegrasper 100 may close the end effector 75. The grasper 100 may include aswitch 118 that allows the user to lock the position of the grasper 100and the end effector 75 of the corresponding medical instrument. Thelocking switch 118 may be coupled to a ratchet (not shown) that allowsthe grasper 100 and corresponding end effector 75 to be locked at one ofa number of positions. The handle 64 may also have a force actuator (notshown) that provides resistance to movement of the grasper 100.

The handle 64 have a plurality of buttons 120, 122 and 124 that can bedepressed by the user. By way of example, button 120 may be used toactivate a cutting mode on a cauterizing end effector. Button 122 may beused to activate a coagulating medical instrument. The button 124 may beused to vary different functions of the system.

FIG. 6 shows one of the surgical instruments 26, 28, 30 or 32. Theinstrument 26, 28, 30 or 32 may include the end effector 75 that iscoupled to an actuator rod 126 located within the instrument shaft 77.The actuator rod 126 is coupled to a motor 130 by an adapter 132. Themotor 130 actuates the end effector 75 by moving the actuator rod 126.The actuator rod 126 is coupled to a force sensor 134 that can sense theforce being applied by the end effector 75. The force sensor 134provides an analog output signal that is sent to a controller 54 shownin FIG. 1. Additionally, the instrument 26, 28, 30, 32 may allowmovement along the arrows 114 and have a force sensor (not shown) tosense force in this direction. Each joint of the robotic arms 34, 36, 38and 40 may also have force sensor that provide feedback to thecontroller 54.

The adapter 132 may be coupled to a gear assembly 136 located at the endof a robotic arm 34, 36, 38 or 40. The gear assembly 136 can rotate theadapter 132 and end effector 75. The actuator rod 126 and end effector75 may be coupled to the force sensor 134 and motor 130 by a springbiased lever 138. The instrument 26, 28, 30 or 32 may be the same orsimilar to an instrument described in the '458 patent.

FIG. 7 depicts the MCU 50 and PCU 52 coupled to the articulate arms 16,18, 20, 22 and 28 by a network port 140 and a pair of interconnectdevices 142 and 144. The network port 140 may be a computer thatcontains the necessary hardware and software to transmit and receiveinformation through a communication link 146 in a communication network148.

The control units 50 and 52 may provide output signals and commands thatare incompatible with a computer. The interconnect devices 142 and 144may provide an interface that conditions the signals for transmittingand receiving signals between the control units 50 and 52 and thenetwork computer 140.

It is to be understood that the computer 140 and/or control units 50 and52 may be constructed so that the system does not require theinterconnect devices 142 and 144. Additionally, the control units 50 and52 may be constructed so that the system does not require a separatenetworking computer 140. For example, the control units 50 and 52 may beconstructed and/or configured to directly transmit information throughthe communication network 148.

The system 10 may include a second network port 150 that is coupled to arobot/device controller(s) 152 and the communication network 148. Thedevice controller 152 controls the articulate arms 16, 18, 20, 22 and24. The second network port 150 may be a computer that is coupled to thecontroller 152 by an interconnect device 154. Although an interconnectdevice 154 and network computer 150 are shown and described, it is to beunderstood that the controller 152 can be constructed and configured toeliminate the device 154 and/or computer 150.

The communication network 148 may be any type of communication systemincluding but not limited to, the internet and other types of wide areanetworks (WANs), intranets, local area networks (LANs), public switchedtelephone networks (PSTN), integrated services digital networks (ISDN).It is preferable to establish a communication link through a fiber opticnetwork to reduce latency in the system. Depending upon the type ofcommunication link selected, by way of example, the information can betransmitted in accordance with the user datagram protocol/internetprotocol (UDP/IP) or asynchronous transfer mode/ATM Adaptation Layer 1(ATM/AAL1) network protocols. The computers 140 and 150 may operate inaccordance with an operating system sold under the designation VxWorksby Wind River. By way of example, the computers 140 and 150 may beconstructed and configured to operate with 100-base T Ethernet and/or155 Mbps fiber ATM systems.

FIG. 8 shows an embodiment of a mentor control unit 50. The control unit50 may be accompanied by a touchscreen computer 156 and an endoscopeinterface computer 158. The touchscreen computer 156 may be a devicesold by Computer Motion under the trademark HERMES. The touchscreen 156allows the surgeon to control and vary different functions andoperations of the instruments 26, 28, 30 and 32. For example, thesurgeon may vary the scale between movement of the handle assemblies 56and movement of the instruments 26, 28, 30 and 32 through a graphicaluser interface (GUI) of the touchscreen 156. The touchscreen 156 mayhave another GUI that allows the surgeon to initiate an action such asclosing the gripper of an instrument.

The endoscope computer 158 may allow the surgeon to control the movementof the robotic arm 42 and the endoscope 44 shown in FIG. 1.Alternatively, the surgeon can control the endoscope through a footpedal (not shown). The endoscope computer 158 may be a device sold byComputer Motion under the trademark SOCRATES. The touchscreen 156 andendoscope computers 158 may be coupled to the network computer 140 byRS232 interfaces or other serial interfaces.

A ZEUS control unit 50 will transmit and receive information that iscommunicated as analog, digital or quadrature signals. The networkcomputer 140 may have analog input/output (I/O) 160, digital I/O 162 andquadrature 164 interfaces that allow communication between the controlunit 50 and the network 148. By way of example, the analog interface 160may transceive data relating to handle position, tilt position, in/outposition and foot pedal information (if used). The quadrature signalsmay relate to roll and pan position data. The digital I/O interface 162may relate to cable wire sensing data, handle buttons, illuminators(LEDs) and audio feedback (buzzers).

The position data is preferably absolute position information. By usingabsolute position information the robotic arms can still be moved evenwhen some information is not successfully transmitted across the network148. If incremental position information is provided, an error in thetransmission would create a gap in the data and possibly inaccurate armmovement. The network computer 140 may further have a screen and inputdevice (e.g. keyboard) 166 that allows for a user to operate thecomputer 140.

FIG. 9 shows an embodiment of a patient side network and controlcomputer. The controller 152 may include three separate controllers168,170 and 172. The controller 168 may receive input commands, performkinematic computations based on the commands, and drive output signalsto move the robotic arms 34, 36, 38 and 40 and accompanying instruments26, 28, 30 and 32 to a desired position. The controller 170 may receivecommands that are processed to both move and actuate the instruments.Controller 172 may receive input commands, perform kinematiccomputations based on the commands, and drive output signals to move therobotic arm 42 and accompanying endoscope 44.

Controllers 168 and 170 may be coupled to the network computer bydigital I/O 176 and analog I/O 174 interfaces. The computer 150 may becoupled to the controller 172 by an RS232 interface or other serial typeinterfaces. Additionally, the computer 150 may be coupled tocorresponding RS232 ports or other serial ports of the controllers 168and 170. The RS232 ports or other serial ports of the controllers 168and 170 may receive data such as movement scaling and end effectoractuation.

The robotic arms and instruments contain sensors, encoders, etc. thatprovide feedback information including force and position data. Some orall of this feedback information may be transmitted over the network 148to the surgeon side of the system. By way of example, the analogfeedback information may include handle feedback, tilt feedback, in/outfeedback and foot pedal feedback. Digital feedback may include cablesensing, buttons, illumination and auditory feedback. The computer 150may be coupled to a screen and input device (e.g. keyboard) 178.Referring to FIG. 7, the computers 140 and 150 may packetize theinformation for transmission through the communication network 148. Eachpacket will contain two types of data, robotic data and other needednon-robotic data. Robotic data may include position information of therobots, including input commands to move the robots and positionfeedback from the robots. Other data may include functioning data suchas instrument scaling and actuation.

Because the system transmits absolute position data the packets ofrobotic data can be received out of sequence. This may occur when usinga UDP/IP protocol which uses a best efforts methodology. The computers140 and 150 are constructed and configured to properly treat any “late”arriving packets with robotic data. For example, the computer 140 maysequentially transmit packets 1, 2 and 3. The computer 150 may receivethe packets in the order of 1, 3 and 2. The computer 150 can disregardthe second packet 2. Disregarding the packet instead of requesting are-transmission of the data reduces the latency of the system. It isdesirable to minimize latency to create a “real time” operation of thesystem.

It is preferable to have some information received in strict sequentialorder. Therefore the receiving computer will request a re-transmissionof such data from the transmitting computer if the data is noterrorlessly received. The data such as motion scaling and instrumentactuation must be accurately transmitted and processed to insure thatthere is not an inadvertent command.

The computers 140 and 150 can multiplex the RS232 data from the variousinput sources. The computers 140 and 150 may have first-in first-outqueues (FIFO) for transmitting information. Data transmitted between thecomputer 140 and the various components within the surgeon side of thesystem may be communicated through a protocol provided by ComputerMotion under the name HERMES NETWORK PROTOCOL (HNP). Likewise,information may be transmitted between components on the patient side ofthe system in accordance with HNP.

In addition to the robotic and non-robotic data, the patient side of thesystem will transmit video data from the endoscope camera 46. To reducelatency in the system, the video data can be multiplexed with therobotic/other data onto the communication network. The video data may becompressed using conventional JPEG, etc., compression techniques fortransmission to the surgeon side of the system.

Each packet may have the fields shown in FIG. 10. The SOURCE ID fieldincludes identification information of the input device or medicaldevice from where the data originates. The DESTINATION ID field includesidentification information identifying the input device or medicaldevice that is to receive the data. The OPCODE field defines the type ofcommands being transmitted.

The PRIORITY field defines the priority of the input device. Thepriority data may be utilized to determine which input device hascontrol of the medical device. The PRIORITY field may contain data thatallows relative shared control of a particular instrument. For example,the mentor may have 50% control and the pupil may have 50% control.

The SEQ # field provides a packet sequence number so that the receivingcomputer can determine whether the packet is out of sequence. The TXRate field is the average rate at which packets are being transmitted.The RX Rate field is the average rate that packets are being received.The RS232 or serial ACK field includes an acknowledgement count forRS232 data. RS232 data is typically maintained within the queue of acomputer until an acknowledgement is received from the receivingcomputer that the data has been received.

The RS232 POS field is a counter relating to transmitted RS232 data. TheRS232 ID field is an identification for RS232 data. The RS232 MESS SZfield contains the size of the packet. The RS232 BUFFER field containsthe content length of the packet. The DATA field contains data beingtransmitted and may contain separate subfields for robotic and RS232data. CS is a checksum field used to detect errors in the transmissionof the packet.

Either computer 140 or 150 can be used as an arbitrator between theinput devices and the medical devices. For example, the computer 150 mayreceive data from both control units 50 and 52. The packets ofinformation from each control units 50 and 52 may include priority datain the PRIORITY fields. The computer 150 will route the data to therelevant device (e.g. robot, instrument, etc.) in accordance with thepriority data. For example, control unit 50 may have a higher prioritythan control unit 52. The computer will route data to control a robotfrom control unit 50 to the exclusion of data from control unit 52 sothat the surgeon at 50 has control of the arm.

As an alternate embodiment, the computer 150 may be constructed andconfigured to provide priority according to the data in the SOURCE IDfield. For example, the computer 150 may be programmed to always providepriority for data that has the source ID from control unit 50. Thecomputer 150 may have a hierarchical tree that assigns priority for anumber of different input devices.

Alternatively, the computer 140 may function as the arbitrator,screening the data before transmission across the network 148. Thecomputer 140 may have a priority scheme that always awards priority toone of the control units 50 or 52. Additionally, or alternatively, oneor more of the control units 50 and/or 52 may have a mechanical and/orsoftware switch that can be actuated to give the console priority. Theswitch may function as an override feature to allow a surgeon to assumecontrol of a procedure.

In operation, the system initially performs a start-up routine. The ZEUSsystem is typically configured to start-up with data from the consoles.The consoles may not be in communication during the start-up routine ofthe robotic arms, instruments, etc. therefore the system does not havethe console data required for system boot. The computer 150 mayautomatically drive the missing console input data to default values.The default values allow the patient side of the system to complete thestart-up routine. Likewise, the computer 140 may also drive missingincoming signals from the patient side of the system to default valuesto allow the control units 50 and/or 52 to boot-up. Driving missingsignals to a default value may be part of a network local mode. Thelocal mode allows one or more consoles to “hot plug” into the systemwithout shutting the system down.

Additionally, if communication between the surgeon and patient sides ofthe system are interrupted during operation the computer 140 will againforce the missing data to the last valid or default values asappropriate. The default values may be quiescent signal values toprevent unsafe operation of the system. The components on the patientside will be left at the last known value so that the instruments andarms do not move.

Once the start-up routines have been completed and the communicationlink has been established the surgeons can operate the consoles. Thesystem is quite useful for medical procedures wherein one of thesurgeons is a teacher and the other surgeon is a pupil. The arbitrationfunction of the system allows the teacher to take control of robotmovement and instrument actuation at anytime during the procedure. Thisallows the teacher to instruct the pupil on the procedure and/or the useof a medical robotic system.

Additionally, the system may allow one surgeon to control one medicaldevice and another surgeon to control the other device. For example, onesurgeon-may move the instruments 26, 28, 30 and 32 while the othersurgeon moves the endoscope 44, or one surgeon may move one instrument26, 28, 30 or 32 while the other surgeon moves the other instrument 26,28, 30 or 32. Alternatively, one surgeon may control one arm(s), theother surgeon can control the other arm(s), and both surgeons mayjointly control another arm.

FIG. 11 shows an alternate embodiment, wherein one or more of thecontrol units 50 and 52 has an alternate communication link 180. Thealternate link may be a telecommunication network that allows thecontrol unit 50 to be located at a remote location while control unit 52is in relative close proximity to the robotic arms, etc. For example,control unit 50 may be connected to a public phone network, whilecontrol unit 52 is coupled to the controller 152 by a LAN. Such a systemwould allow telesurgery with the robotic arms, instruments, etc. Thesurgeon and patient sides of the system may be coupled to the link 180by network computers 182 and 150.

FIG. 12 shows a schematic of a control system 190 to allow joint controlof a single medical instrument with handles from two different controlunits 50 and 52. The control system 190 may include an instrumentcontroller 192 coupled to a medical instrument 26, 28, 30 and 32. Theinstrument controller 192 minimizes the error between the desiredposition x_(des) of the medical instrument 26, 28, 30 or 32 and theactual position x of the instrument 26, 28, 30 or 32.

The instrument controller 192 is coupled to the position controllers 194and 196 for the MCU 50 and PCU 52, respectively. The positioncontrollers 194 and 196 are each connected to a corresponding handlecontroller 198 and 200, respectively, which is coupled to the handles 56of each control unit. The handle controllers 198 and 200 provide outputx₁ and x₂, respectively, that corresponds to the movement of the handles56. The output is transformed to position output signals to drive theactuators of the medical instrument 26, 28, 30 or 32. The value ofx_(des) can be computed from x.sub.1 and x.sub.2 and a proportionalcontrol variable.

The instrument controller 192 also computes force feedback informationfrom the force sensors of the instrument. The force feedback informationis relayed back to the handle controllers 198 and 200 and handles 56 toprovide force feedback to the surgeon. The amount of force feedback toeach set of handles may depend on the shared control of the mentor 50and pupil 52 control units.

Referring to FIG. 13, the displacements of the mentor and pupil arerepresented by x₁ and x₂, respectively. The motion of the instrument isa convex combination of the motion of the mentor and pupil, namely,

x=(1−α)x ₁ +αx ₂  (1)

The springs in FIG. 13 are undeformed when x₁=x₂, irrespective of thevalue of α.

When x₁≠x₂, the deformation of the spring at the mentor end is

x−x ₁=α(x ₂ −x ₁)  (2)

The mentor therefore feels the force

F ₁ =Kα(x ₂ −x ₁)  (3)

Where K is the spring constant.

At the same time, the deformation of the spring at the pupil end is:

(x ₂ −x)=(1−α)(x ₂ −x ₁)  (4)

The pupil therefore feels the force:

F ₂ =K(1−α)(x ₂ −x ₁)  (5)

There are typically a set of equations to determine the movement x andforce feedback F₁ and F₂ for each axis of each instrument. There mayalso be a set of equations for actuation of each end effector. Forangular movement the distance is typically computed in degrees, radiansor some other angular unit of measure.

When the mentor has complete control, α is set to 1 and the mentorhandles provide no force feedback. The variable α can be set through thecomputer interfaces of the system 10. The force feedback to the pupilhandles corresponds to the position information generated by the mentorhandles and the position information generated by the pupil handles.Thus if the pupil handle movement deviates from the mentor handlemovement, the system provides α force feedback to push the pupil intothe desired hand movement. This is similar to teaching one to write witha pencil by grabbing their hand and moving the pencil. The system thusallows the mentor to guide the pupil through the motion of using thehandles to move the medical instrument and perform a medical procedure.This can be a valuable instructional guide in learning how to use thesystem and perform robotically assisted minimally invasive procedures.

The proportional variable α allows the mentor and pupil to jointlycontrol the movement of an instrument 26, 28, 30 and/or 32. Theinstrument controller 192 can compute the x_(des) using equation (3).The feedback forces F₁ and F₂ are computed using equations (1) and (2)and fed back to the mentor and pupil through the force actuator for eachjoint.

In operation, the users may set the value of α. For example, a may beset at 0.5 for split control. Both the mentor and pupil move theirhandles a distance x₁ and x₂, respectively. There may in fact bemultiple movements including wrist and roll movement. The controllerscompute the corresponding movement x from the equation and drive therobotic arm to move the instrument. The controllers also calculate theforces F₁ and F₂ and drive the force actuators for each correspondingjoint. If the pupil's and mentor's movements are in sync then the systemdoes not provide force feedback. If the movements are out of sync thesystem provides a force feedback that allows the participants to “feel”the discrepancy between their movement commands.

While certain exemplary embodiments have been described and shown in theaccompanying drawings, it is to be understood that such embodiments aremerely illustrative of and not restrictive on the broad invention, andthat this invention not be limited to the specific constructions andarrangements shown and described, since various other modifications mayoccur to those ordinarily skilled in the art.

Although force feedback is described, it is to be understood that othermeans for showing pupil handle deviation may be used in the system. Forexample, the system may have a visual indicator such as a bar graph thatindicates the deviation between the mentor and pupil handles.

1-8. (canceled)
 9. A medical robotic system, comprising: a first medicaldevice; a first input device that can be moved a first input distance tomove said first medical device; a second input device that can be moveda second input distance to move said first medical device; and, aninstrument controller programmed to generate and provide a movementcommand for the first medical device including a sum of first and secondproducts wherein the first product is of the first input distance and afirst factor that is proportional to the number one minus a usersettable parameter value and the second product is of the second inputdistance and a second factor that is proportional to the user settableparameter value; generate and provide a first visual indication so as tobe viewable by a first operator of the first input device wherein thefirst visual indication is proportional to a third product of the usersettable parameter value and a difference between the first and secondinput distances; and generate and provide a second visual indication soas to be viewable by a second operator of the second input devicewherein the second visual indication is proportional to a fourth productof the number one minus the user settable parameter value and thedifference between the first and second input distances.
 10. The systemof claim 9, wherein the first and second visual indications are providedon first and second bar graphs respectively viewable by the first andsecond operators of said first and second input devices.
 11. A medicalrobotic system, comprising: a first medical device; first input meansthat can be moved a first input distance for moving said first medicaldevice; second input means that can be moved a second input distance formoving said first medical device; and controller means for generatingand providing a movement command for the first medical device includinga sum of first and second products wherein the first product is of thefirst input distance and a first factor that is proportional to thenumber one minus a user settable parameter value and the second productis of the second input distance and a second factor that is proportionalto the user settable parameter value; generating and providing a firstvisual indication so as to be viewed by a first operator of the firstinput device wherein the first visual indication is proportional to athird product of the user settable parameter value and a differencebetween the first and second input distances; and generating andproviding a second visual indication so as to be viewed by a secondoperator of the second input device wherein the second visual indicationis proportional to a fourth product of the number one minus the usersettable parameter value and the difference between the first and secondinput distances.
 12. The system of claim 11, wherein the first andsecond visual indications are provided on first and second bar graphsrespectively viewable by the first and second operators of said firstand second input devices.
 13. A method for controlling a first medicaldevice, comprising: detecting movement of a first input device so as todefine a first input distance; detecting movement of a second inputdevice so as to define a second input distance; commanding a firstmedical device to be robotically moved according to a movement commandincluding a sum of first and second products wherein the first productis of the first input distance and a first factor that is proportionalto the number one minus a user settable parameter value and the secondproduct is of the second input distance and a second factor that isproportional to the user settable parameter value; generating first andsecond visual indications, wherein the first visual indication isproportional to a third product of the user settable parameter value anda difference between the first and second input distances and the secondvisual indication is proportional to a fourth product of the number oneminus the user settable parameter value and the difference between thefirst and second input distances; and providing said first visualindication so as to be capable of being viewed by a first operatoroperating said first input device, and providing said second visualindication so as to be capable of being viewed by a second operatoroperating said second input device.
 14. The method of claim 13, furthercomprising generating said movement command according to the followingequation:x=(1−α)x ₁₊ αx ₂, where x is a distance that the medical device is to berobotically moved.
 15. The method of claim 13, further comprising:displaying the first visual indication so as to be viewable by a firstoperator manipulating said first input device; and displaying the secondvisual indication so as to be viewable by a second operator manipulatingsecond input device.
 16. The method of claim 15, wherein said firstvisual indication is a first bar graph displayed on a first monitorviewable by said first operator.
 17. The method of claim 16, whereinsaid second visual indication is a second bar graph displayed on asecond monitor viewable by said second operator.